if i were you i wouldn't start the whole time travel isn't possible in real life conversation because it will just open a really big can of worms and a argument will start about it and it hasn't been proven either way in science at all.

See, this is what bugged me about the whole "death of the Doctor" malarkey...

Nobody could possibly know when/if a time travelling do-gooder had died, or care about it, because his ability to time-travel would mean that he'd continue to appear in the future to foil your plans regardless of whether he was "dead" or not.

If I was a dalek, what I'd do would be to look at a history book, find a time when The Doctor was busy foiling a dastardy plot in one place and then time-travel to a different place to hatch my evil schemes.

The only problem with that is, similar to what you correctly stated about the doctor being dead at one point but a past version appearing in the future, the dalek could look up and see that 12 was busy in a particular time period so go somewhere else, he could be stopped by 12 from a week/month/year in the future or past in his timeline. A better idea would be to look up where he was busy then go to that time but in a different part of the universe, but even then if 12 was busy in that time and place you might think your safe only for the fourth doctor to turn up and foil your plan for example.

With Just the doctors we know so far, that's multiple versions of the same man all traveling all across time and space, actively looking for adventure and his TARDIS taking him to where he is needed to sort out the wrongdoing of the universe. Basically, in the dw universe, if your doing wrong,particularly if your a dalek, he's going to find out eventually